
Calendar of Physics Talks Vienna
Micromanipulation, quantum metrology and vacuum forces: a unified perspective based on the scattering matrix (Vienna Theory Lunch Seminar) 
Speaker:  Lukas Rachbauer (TU Wien) 
Abstract:  We introduce the quantum WignerSmith (QWS) operator, a Hermitian operator describing the interaction between the spatial as well as the quantum degrees of freedom of light and a local classical parameter of a linear, but otherwise arbitrarily complex scattering medium through which the light propagates. The QWS operator builds a bridge between quantum micromanipulation, vacuum forces and quantum metrology on the one side, and the formalism of classical scattering matrices, which are experimentally measurable in a noninvasive manner, on the other side. [...]
[[part of the "Vienna Theory Lunch Seminar, see https://lunchseminar.univie.ac.at, please find also the full abstract on the web page]] 
Date:  Tue, 14.11.2023 
Time:  12:30 
Duration:  75 min 
Location:  TU Wien: Wiedner Hauptstr. 810, yellow area, 10th floor, seminar room DB10E11 
Contact:  Florian Lindenbauer 
Cosmic Imprints of Quantum Gravity: Insights from the Swampland Program 
Speaker:  Marco Scalisi (Max Planck Institute for Physics, Munich) 
Abstract:  Common lore suggests that effects of quantum gravity are difficult to unravel. The Planck scale is in fact about 15 orders of magnitude above the highest energy reached on Earth, namely at the Large Hadron Collider. The Swampland program suggests instead that the quantum gravity cutoff can decrease thus making quantum gravity effects accessible at energies lower than the Planck scale. In this talk, I will first review some basics of Swampland program; I will then concretely show how the quantum gravity cutoff can drop in certain situations; I will finally explore the implications of this fact for cosmology. 
Date:  Tue, 14.11.2023 
Time:  14:00 
Duration:  60 min 
Location:  Sem. R. DB gelb 03  TU Wien Freihaus (Wiedner Hauptstrasse 8, 3rd floor, yellow tower) 
Contact:  Stefan Fredenhagen, Tung Tran, Adrien Fiorucci 
Weyl channels for multipartite systems 
Speaker:  JosÃ© Alfredo de LeÃ³n (Instituto de FÃsica, Universidad Nacional AutÃ³noma de MÃ©xico) 
Abstract:  Quantum channels describe the unitary and nonunitary evolution of quantum systems. We study a generalization of the concept of Pauli maps to the case of multipartite high dimensional quantum systems through the use of the Weyl operators. The condition for such maps to be valid quantum channels, i.e. complete positivity, is derived in terms of Fourier transform matrices. From these conditions, we find the extreme points of this set of channels and identify an elegant algebraic structure nested within them. In turn, this allows us to expand upon the concept of âcomponent erasing channelsâ. We show that these channels are completely characterized by elements drawn of finite cyclic groups.

Date:  Wed, 15.11.2023 
Time:  11:00 
Duration:  45 min 
Location:  Seminarroom ZE 011 
Contact:  Marcus Huber 
From the WeylSchrÃ¶dinger connection to the accelerating Universe  extending Einstein's gravity via a length preserving nonmetricity 
Speaker:  Tiberiu Harko (BabesBolyai U) 
Abstract:  One of the important extensions of Riemann geometry is Weyl geometry, which is essentially based on the ideas of conformal invariance and nonmetricity. A similar nonRiemannian geometry was proposed by Erwin SchrÃ¶dinger in the late 1940s, in a geometry which is simpler, and (probably) more elegant than the Weyl geometry. Even it contains nonmetricity, the SchrÃ¶dinger connection preserves the length of vectors under parallel transport,and thus seems to be more physical than the Weyl connection. Interestingly enough, SchrÃ¶dinger's approach did not attract much interest in the field of gravitational physics.It is the goal of the present talk to reconsider the SchrÃ¶dinger geometry as a potential candidate for a gravitational theory extending standard general relativity. We consider a gravitational action constructed from a length preserving nonmetricity, in the absence of torsion . . . . 
Date:  Wed, 15.11.2023 
Time:  14:15 
Duration:  60 min 
Location:  Seminarraum A, Waehringer StraÃe 17, 2. Stock 
Contact:  P. Chrusciel, D. Fajman 
Symplectic structure of the JackiwTeitelboim gravity 
Speaker:  Anton Alekseev (University of Geneva) 
Abstract:  The JackiwTeitelboim (JT) gravity has recently attracted a lot attention because it gives a simple and yet nontrivial example of holographic duality.
In this talk, we discuss the symplectic structure associated to the JT gravity. This topic was pioneered by SaadShenkerStanford and by StanfordWitten.
We will argue that the infinite dimensional TeichmÃ¼ller space associated to a hyperbolic surface with boundary at infinity carries a canonical symplectic structure which arises through Hamiltonian reduction.
This reduction procedure is rather standard in the bulk and it has novel features at the boundary of the surface.
In particular, the TeichmÃ¼ller space carries an action of the diffeomorphism group of the boundary with a non vanishing Virasoro central charge.
The talk is based on a joint work in progress with Eckhard Meinrenken. 
Date:  Thu, 16.11.2023 
Time:  13:15 
Duration:  60 min 
Location:  Erwin Schroedinger Institute for Mathematics and Physics, Schroedinger lecture hall  Boltzmanngasse 9, 2nd floor 
Contact:  S. Fredenhagen, H. Steinacker 
Cosmological models: Hierarchies of asymptotic behaviour 
Speaker:  Helmut Friedrich (AEI Potsdam) 
Abstract:  De Sitter spacetime is a geodesically complete,conformally flat, spatially compact solution to the EinsteinÎ»vacuum equations with cosmological constant Î» that admits smooth conformal boundaries ${\cal J}^{\pm}$ at future and past timelike infinity.Data sufficiently close to de Sitter data develop into solutions to the EinsteinÎ»vacuum equations that admit smooth conformal boundaries as well.These solutions extend,as solutions to the conformal Einstein equations,beyond these boundaries where they define again solutions to the EinsteinÎ»vacuum equations. Gravitational radiation, i.e. perturbations to the conformal Weyl tensor,travels unimpeded across ${\cal J}^{\pm}$ into the extended domain. We discuss our interest in this phenomenon and the question to what extent it generalizes to the future developments of solutions to the EinsteinÎ» equations coupled to various matter fields. 
Date:  Thu, 16.11.2023 
Time:  15:15 
Duration:  60 min 
Location:  Seminarraum A, Waehringer StraÃe 17, 2. Stock 
Contact:  P. Chrusciel, D. Fajman 
New platforms for quantum sensing and quantum computing 
Speaker:  Nathalie P. de Leon (Princeton University) 
Abstract:  The nitrogen vacancy (NV) center in diamond exhibits spindependent fluorescence and long spin coherence times under ambient conditions, enabling applications in quantum information processing and sensing. NV centers near the surface can have strong interactions with external materials and spins, enabling new forms of nanoscale spectroscopy. However, NV spin coherence degrades within 100 nanometers of the surface, suggesting that diamond surfaces are plagued with ubiquitous defects. I will describe our recent efforts to correlate direct materials characterization with single spin measurements to devise methods to stabilize highly coherent NV centers within nanometers of the surface. We deploy these coherent shallow NV centers for a new nanoscale sensing technique, whereby we use covariance measurements of two or more NV centers to measure twopoint magnetic field correlators.
Our approa 
Date:  Fri, 17.11.2023 
Time:  10:00 
Duration:  45 min 
Location:  Helmut Rauch HÃÂ¶rsaal ATI 
Contact:  Andrew Kanagin 
QCD at high energies: Wilson lines in the CGC and jets 
Speaker:  Heribert Weigert (University of Cape Town) 
Abstract:  I will provide an introduction to the ideas behind the Color Glass Condensate and the JIMWLK evolution equation.
I will introduce a counterpart to structure functions for Wilson line correlators and provide some insight into the
diverse role of color singlets in evolution equations involving Wilson line correlators.
To wit, these structures also occur in the evolution of certain jet observables.
I will further explore the structural relationship of evolution equations in the CGC and jet context (JIMWLK vs BMSW) using a conformal map.

Date:  Fri, 17.11.2023 
Time:  14:00 
Duration:  60 min 
Location:  KurtGoedelHoersaal, Fakultaet fuer Physik, Boltzmanngasse 5, Erdgeschoss 
Contact:  A. Hoang, M. Procura, S. Plaetzer 
Power corrections to collider observables 
Speaker:  Kirill Melnikov (KIT) 
Abstract:  I will present the recent attempts to optimize the computation of power corrections to collider
observables in the context of renormalon calculus. Examples related to top quark production processes
at a hadron collider and jet production in electronpositron collisions will be discussed.

Date:  Fri, 17.11.2023 
Time:  16:15 
Duration:  60 min 
Location:  Fakultaet fuer Physik, Josef StefanHS, Boltzmanngasse 5, 3. Stock 
Contact:  A. Hoang, M. Procura 
